The invention relates to a method of controlling a closure drive system of a motor vehicle that moves a component between open and closed positions.
Electronic control devices are usually used to control a closure drive system of a motor vehicle, such as that of a window lifter system or sliding roof system, for example. For a better understanding of the invention, reference is made to a control device that is arranged in a door of the vehicle, and which is part of the window lifter system. In this example, the control device is not only capable of controlling an electric window lifter, but could also control a door lock or an electrically adjustable outside mirror.
Window lifter systems are required to have pinch protection that is supposed to prevent an object from getting pinched during closing of a window. In these systems, the pinch protection is controlled based on certain vehicle parameters because the maximum forces that are admissible for a stationary vehicle are different from those for a moving vehicle. Also, the effects of an acting wind load, for example, have to be taken into consideration for pinch protection during a displacement of the window with a moving vehicle. This is why a differentiation between moving and stationary vehicles is necessary in a pinch protection system.
It is known that some pinch protection systems, which differentiate between moving and stationary vehicles, immediately use vehicle speed information. This information is typically made available via a bus system, for instance. A bus system, however, is a very expensive vehicular system that is often omitted in some vehicle types for reasons of economy. In these instances, it will not be possible to obtain vehicle speed information and, hence, on a vehicle parameter that is important for the operation of the pinch protection system.
Other known pinch protection systems are controlled by an enabling signal, which uses signals from vehicle doors and from an ignition lock in order to differentiate whether the vehicle is moving or not. This differentiation is not easy and can be inaccurate because, for instance, with the vehicle door in a closed state and a key inserted in the ignition lock, the engine may or may not be running. Thus, it is possible that parameters for a moving vehicle are incorrectly used with a stationary vehicle. Also, in such systems, additional signal lines are needed for the control device (e.g. vehicle speed signal).
It is therefore the object of the invention to provide a method of controlling a pinch protection system for a closure system that ensures an effective and low cost pinch protection without requiring a bus system or additional signal lines.